1. Field of the Invention
The present invention relates to a liquid composition, an ink set for ink-jet recording, an ink-jet recording process, a recording unit and an ink-jet recording apparatus, and more particularly to a liquid composition and an ink set for ink-jet recording, which can form images with decreased bleeding and excellent water fastness, and an ink-jet recording process, a recording unit and an ink-jet recording apparatus using either one of these composition and ink set.
2. Related Background Art
An ink-jet recording method is a recording method of low noise and nonimpact in which an ink is directly ejected on a recording medium to record an image. This method is easy to reduce running cost, miniaturize an apparatus and form color images because no complicated apparatus is required upon practice thereof. Therefore, recording apparatus such as printers, copying machines, facsimiles and word processors, to which the ink-jet recording method is applied, have heretofore been put into practical use. A color ink-jet recording apparatus have also been put into practical use for forming multi-color images with a black ink and color ink(s) (for example, at least one color ink selected from yellow, cyan, magenta, red, green and blue inks) using such an ink-jet recording technique.
On the other hand, image formation by the ink-jet recording method involves a problem that there occurs a phenomenon (bleeding) that when two inks of different kinds are applied adjoiningly on a recording medium, the inks are mixed with each other at boundaries between them to deteriorate the quality of a color image formed. In particular, color mixing at boundaries between a black ink and a color ink greatly affects deterioration of image quality, so that various solving methods have been developed.
A representative solving method is an ink set and a recording method having a mechanism that when two inks are applied adjoiningly on a recording medium, viscosity increase of at least one ink or aggregation or precipitation of at least one ink is caused to prevent bleeding.
As described in, for example, Japanese Patent Application Laid-Open No. 5-202328, U.S. Pat. No. 5,198,023 and Japanese Patent Application Laid-Open No. 6-106841, there are disclosed techniques for controlling color bleeding by using a first liquid containing a precipitant and a second liquid containing a coloring material capable of forming precipitate by the precipitant in combination. Polyvalent metal salts are disclosed as the precipitant, and dyes having at least one carboxyl group, and the like are disclosed as the coloring materials capable of precipitating by the polyvalent metal salts. The first liquid may contain a coloring material. In this case, the first liquid may also be used as an ink. However, all these polyvalent metal salts use a Clxe2x88x92, NO3xe2x88x92, Ixe2x88x92, Brxe2x88x92, ClO3xe2x88x92 or CH3COOxe2x88x92 ion as an anion in the polyvalent metal salts. Further, Japanese Patent Application Laid-Open No. 2000-136337 discloses, as precipitants, metal-coordinated compounds with a polyvalent metal ion coordinated to a compound having a ligand, such as lactic acid, in addition to the above-described polyvalent metal salts.
The present inventors have carried out an extensive investigation with a view toward improving bleeding. As a result, it has been found that when a first liquid containing a polyvalent metal salt of aldonic acid and a second liquid containing a coloring material capable of reacting with the polyvalent metal salt of aldonic acid are used in combination, and when these liquids are applied onto a recording medium so as to form a contact state, the coloring material reacts with the polyvalent metal ion to lessen occurrence of bleeding. The term xe2x80x9creactionxe2x80x9d as used in the present invention means to cause aggregation, precipitation or viscosity increase of the second liquid and also includes a reaction after these liquids penetrate into the recording medium. It has further found that polyvalent metal salts of aldonic acid are excellent in solubility in an ink, can be effectively utilized as a component of the ink and is very safe against the human body. It has also been confirmed that improvement in water fastness is observed when the first liquid and second liquid are applied so as to overlap each other.
It is therefore an object of the present invention to provide a liquid composition which can alleviate occurrence of bleeding when used in an ink-jet recording method together with an color ink and can form high-quality images improved in water fastness.
Another object of the present invention is to provide an ink set which permits the formation of high-quality images with lessened occurrence of bleeding and having excellent water fastness.
A further object of the present invention is to provide an ink-jet recording process which can form images having good water fastness.
A still further object of the present invention is to provide an ink-jet recording process which can form color images in which bleeding at boundaries between adjacent inks of different colors is alleviated.
A yet still further object of the present invention is to provide an ink-jet recording apparatus which can be suitably used for the formation of color images having lessened occurrence of bleeding and images having good water fastness.
A yet still further object of the present invention is to provide a recording unit which can be suitably used in the ink-jet recording apparatus.
The above objects can be achieved by the present invention described below.
According to an embodiment of the present invention, there is thus provided a liquid composition for an ink jet recording which is used together with a color ink and reacts with the color ink when it comes into contact with the color ink, which comprises a polyvalent metal salt of aldonic acid and a liquid medium.
According to an embodiment of the present invention, there is also provided an ink-jet recording process, comprising the steps of:
(i) applying energy to the liquid composition described above to eject it toward a recording medium;
(ii) applying energy to a color ink to eject it toward a recording medium; and
(iii) forming a contact state of the liquid composition with the color ink on the recording medium.
According to an embodiment of the present invention, there is further provided an ink set for ink-jet recording, comprising
(1) the liquid composition described above, and
(2) a color ink which comprises a coloring material and a liquid medium and reacts with the liquid composition by in contact with the liquid composition.
According to an embodiment of the present invention, there is still further provided a recording unit, comprising a liquid composition container portion containing the liquid composition described above, an ink container portion containing a color ink, and an ink-jet recording head for ejecting the liquid composition and the color ink by applying energy to the liquid composition and the color ink.
According to an embodiment of the present invention, there is yet still further provided an ink-jet recording apparatus, comprising a liquid composition container portion containing a liquid composition, an ink container portion containing a color ink, and an ink-jet recording head for ejecting the liquid composition and the color ink by applying energy to the liquid composition and the color ink, wherein the liquid composition is the liquid composition described above.
According to another embodiment of the present invention, there is yet still further provided an ink-jet recording apparatus comprising the recording unit described above.
According to another embodiment of the present invention, there is yet still further provided an ink set for ink-jet recording, comprising
(1) a color ink comprising a coloring material, a liquid medium and a polyvalent metal salt of aldonic acid, and
(2) a black ink which comprises a coloring material and a liquid medium and reacts with the color ink by contact with the color ink.
According to another embodiment of the present invention, there is yet still further provided an ink-jet recording process, comprising the steps of:
(i) applying energy to the black ink contained in the ink set described above to eject it toward a recording medium;
(ii) applying energy to the color ink contained in the ink set described above to eject it toward a recording medium; and
(iii) forming a contact state of the black ink with the color ink on the recording medium.
According to another embodiment of the present invention, there is yet still further provided a recording unit, comprising an ink container portion containing the ink set described above and an ink-jet recording head for ejecting the inks being fed from the ink container portion by applying energy to the inks.
According to another embodiment of the present invention, there is yet still further provided an ink-jet recording apparatus, comprising an ink container portion containing an ink set comprising at least a black ink and a color ink and an ink-jet recording head for ejecting the ink being fed from the ink container portion by applying energy to the ink, wherein the ink set is the ink set described above.
According to a further embodiment of the present invention, there is yet still further provided an ink-jet recording apparatus comprising the recording unit described above.